High-power DC voltage electrical systems are the subject of a significant development. Indeed, many transport systems include a DC power supply.
Internal combustion/electric hybrid or electric vehicles notably include high-power batteries. In order to obtain a sufficient voltage level, several electrochemical accumulators are placed in series. In order to obtain high powers and capacities, several groups of accumulators are placed in series. The number of stages (number of groups of accumulators) and the number of accumulators in parallel in each stage vary depending on the desired voltage, on the desired current and on the desired capacity for the battery. The association of several accumulators is called a battery of accumulators.
Such batteries are generally used for driving an AC electric motor by means of an inverter. The levels of voltage needed for such motors reach several hundreds of Volts, typically around 400 volts. Such batteries also comprise a high capacity in order to promote the autonomy of the vehicle in electric mode. Several technical reasons specific to their use in automobiles lead to the use of an insulation between the body, or mechanical ground, of the vehicle (formed by the chassis and the metal bodywork of the vehicle, and therefore accessible to the user) and the potentials of the battery.